Due to their low-power requirements and fail safe property, magneto-rheological (MR) dampers have been enjoying renewed interest as an attractive means for protecting civil infrastructure systems against severe earthquake and wind loading. Several approaches have been proposed to control the MR dampers. The study shows that shear response and flexural response of buildings present two very different cases for vibration suppression. New bracings-lever mechanism configurations are proposed for the dampers to improve their performance. The results shows how the proposed configurations can enable application to flexural response and scenarios where the inter-story drift is not sufficient for dampers to work effectively.
Recent research carried out on controlled buildings under earthquakes shows that the MR damper is highly controllable and the application of its controllability is fruitful. The controllable nature of the MR damper permits achieving different control objectives (e.g., reducing floor displacements, drifts, and absolute accelerations) by using various control algorithms. In any case, research towards a new controller is still promising. The door is open for interested researchers to come up with new methodology.
The use of smart dampers in civil engineering structures for vibration attenuation has proven to be promising in recent years. Nevertheless, evaluating the effectiveness of smart dampers in multiple-degree-of-freedom (MDOF) dynamic systems is a time-consuming task. This hurdle hinders the consideration of potential families of controllers for a reliable design and tuning process. Consequently, the current study develops a probabilistic approach by introducing a new theory of semiactive control gains to enable the solution of highly nonlinear control systems with smart dampers by employing the Lyapunov function. The primary objective is to test a hypothesis that the tuning of controlled semiactive dampers in MDOF systems can be performed analytically without the burden of numerical simulations. As opposed to current simulation methods, the proposed probabilistic approach can be used to significantly reduce computational efforts. Accordingly, the proposed approach is useful for the design and evaluation of the efficacy of smart dampers in MDOF systems, such as multistory buildings and wind turbines. In addition, the developed control theory will enable the use of accelerated performance-based semiactive controller tuning, with a potential to advance innovative technologies for building smart, resilient, and sustainable structures that can survive multiple hazards.
- Rezaee, M., Aly, A.M. (2019), "Proposed Theory of Semiactive Gains for Smart Dampers in MDOF Systems," Journal of Structural Engineering, ASCE, 145(12). DOI: 10.1061/(ASCE)ST.1943-541X.0002453
- Rezaee, M., Aly, A.M. (2018), "Vibration Control in Wind Turbines to Achieve Desired System-Level Performance under Single and Multiple Hazard Loadings," Structural Control and Health Monitoring, 25(12), e2261. DOI:10.1002/stc.2261
- Aly, A.M. (2016), "The Use of Bracing Systems with MR Dampers in Super Tall Buildings", International Journal of High-Rise Buildings (IJHRB), 5(1), 31-41.
- Aly, A.M., (2015), "Control of wind-induced motion in high-rise buildings with hybrid TM/MR dampers", Wind and Structures, 21(5), 565-595.
- Aly, A.M. "Vibration Control of Buildings Using Magnetorheological Damper: A New Control Algorithm," Journal of Engineering, Volume 2013, Article ID 596078, 10 pages, 2013. DOI: http://dx.doi.org/10.1155/2013/596078